This application seeks partial funding for the FASEB 2002 Summer Research Conference on Tetraspanins to be held June 15- June 20, 2002 in Tucson, Arizona. This will be the second conference ever to be dedicated to this superfamily of widely expressed, multifunctional proteins. The interest in the family has been growing rapidly with new members being identified in a wide range of species including mammals, nematodes, drosophila, and Schistosomes. A few areas of recent progress include the solving of the structure for the large extracellular loop of CD81, the identification of a host of other proteins that are either tightly or loosely associated with tetraspanins, and the production of several knockout mice. More so than ever before, researchers in the field are now poised to uncover fundamental mechanisms behind the contributions of tetraspanins towards cell motility, fusion, signaling, and other function. The conference will cover recent progress in areas of relevance to infectious disease (binding of hepatitis C virus, diphtheria toxin, virus induced syncytia formation), brain function (neurite outgrowth, astrocyte, schwann cell, oligodendrocyte functions), fertility (sperm-egg fusion), development/differentiation (myogenesis, osteogenesis and hematopoiesis, bladder development), immune function (T and B cell signaling, co-stimulation, TH1/TH2 ratios, IgM production), tumor growth and metastasis (tumor suppression, metastasis promotion), and other human diseases, retinal disease, X-linked mental retardation). There has been only one previous tetraspanin conference (in July, 2000), and that was overwhelmingly successful. No other related conferences are scheduled. The meeting will follow the standard FASEB meeting format, with 9 sessions, over 4.5 days, with 3-4 major presentations in each session. Invited attendees will include a broad spectrum of clinicians, oncologists, cell and developmental biologists, immunologists, and basic biochemists and molecular biologists. Every attempt will be made to have a balanced distribution of presenters and attendees (new, established; academic, industrial; male, female; USA, other countries; etc.). With researchers from so many diverse area being brought together, common themes relevant to human pathophysiological processes should emerge. With the recent application of newly available genomic, proteomic, and genetic technologies, an abundance of new information should be forthcoming.